何梓荐,黄雪飞,乐国敏,付宝勤.钨中溶质原子铬与空位的相互作用的第一性原理计算研究[J].稀有金属材料与工程,2020,49(8):2691~2696.[He Zijian,Huang Xuefei,Le Guomin,Fu Baoqin.Study of the interaction between the solute Cr atoms and vacancy in W-Cr alloys using first-principles calculation[J].Rare Metal Materials and Engineering,2020,49(8):2691~2696.]
钨中溶质原子铬与空位的相互作用的第一性原理计算研究
投稿时间:2019-07-30  修订日期:2019-09-06
中文关键词:  第一性原理,钨-铬合金,空位缺陷
基金项目:国家自然科学基金资助(项目号51501119)
中文摘要:
      钨铬(W-Cr)合金具有优异的物理性能,被认为是面向等离子体材料(PFM)中最有潜力的候选材料。而合金元素对辐照损伤演化过程的影响规律是钨合金优化设计的关键,深入研究溶质原子与辐照缺陷(如:空位)的相互作用有助于理解辐照损伤演化的微观物理机制。本文基于第一性原理方法,对W-Cr合金的溶质原子Cr占位、Cr与空位的相互作用及Cr含量对其影响规律进行了计算研究。发现相比于间隙位置,原子Cr更易占据置换位置,W中溶质Cr有偏聚的趋势;在辐照环境下,空位和自间隙原子均易与溶质原子Cr相结合,易加速W中富Cr相的析出;随Cr含量的增加,体系的形成能线性增加,因而结构越发不稳定。研究还发现超胞中单原子Cr的第二近邻空位的形成能最低,且低于W的本征空位形成能,因而溶质Cr与空位之间存在微弱的吸引;对于同一Cr含量,不同构型的空位形成能及空位和Cr的结合能均不同,且Cr含量越高,数值越分散;随着Cr含量的增加,平均空位形成能及空位与Cr的平均结合能均略有下降,因而溶质原子Cr附近空位更易形成,空位浓度更高,同样也表明溶质Cr与空位有微弱的吸引。这些结论将有助于深入理解W中溶质元素存在条件下辐照缺陷演化过程的微观物理机制。
Study of the interaction between the solute Cr atoms and vacancy in W-Cr alloys using first-principles calculation
英文关键词:first-principles, W-Cr  alloys, vacancy
英文摘要:
      Tungsten-chromium alloy (W-Cr alloy) is a primary candidate for plasma-facing materials (PFM) in future fusion devices because of its excellent properties. The knowledge of the interaction between solute Cr atoms and vacancy in W-Cr alloys is the key to understand the mechanism of the evolution of radiation damage. In this work the occupation of solute Cr atoms, the interaction between solute Cr atoms and vacancy, and the effect of the solute Cr concentration were studied by first-principles calculation. We found that the solute Cr atoms prefers to occupy the substitutional position with formation energy of ~0.3eV. The point defects induced by radiation will facilitate the segregation of the solute Cr atoms. The formation energy of solute Cr increases linearly with increasing of the concentration of solute Cr, indicating a strong segregation. It was also found that there exists a very weak attractive interaction between the solute Cr atoms and vacancy, and the interaction tends to be stronger when the concentration of the solute Cr increases. These results are important for understanding the long-term micro-structural evolution of materials under irradiation.
作者单位E-mail
何梓荐 四川大学 740408120@qq.com 
黄雪飞 四川大学  
乐国敏 中国工程物理研究院材料研究所  
付宝勤 四川大学 bqfu@scu.edu.cn 
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